No, there is no true Black or Blue roses in nature. There are roses that are called black roses or blue roses but these are usually just very deep red or purple roses. In the case of blue roses they are actually a purple rose with a bluish tint. In another example of a not so true black or blue rose, white roses are sometimes dyed to look black or blue. Until now it has not been possible to produce a blue rose, with most roses called 'blue' being shades of lavender or purple. The CSIRO have claimed to have produced a truly blue rose, and there is a link to their Web site to the left under Web Links. This also includes a discussion on why there have been no blue roses so far.
There are no black roses, only in fiction. Roses that are called 'black' are actually dark red.
ANSWER: In all rose varieties, one color was long missing-blue. The gene for producing blue, delphinidin, does not occur naturally in the rose family. However, after years of joint research by an Australian company and a Japanese company, a "blue" rose was created in 2004 using genetic engineering. Further effort is needed, though, to achieve a bluer hue. from Awake magazine article